In accordance with an embodiment, described herein is a system and method for decoupling a source application and a target application using a messaging service associated with a cloud-based integration service. A first integration flow can be provided to enable the source application or producer to publish messages to the messaging service. A second integration flow can be provided to enable the target application or consumer to subscribe to the messaging service to receive messages. The source application and the target application can be agnostic of each other's implementation details, and those of the messaging service, which effectively decouples the source and target applications. The system enables objects between the source and target applications to be sychronized, multiple applications to subscribe to the integration cloud service and register for updates, and one or more applications to be added or removed as subscribers without affecting other subscribers or producers.